The last show of the concert at the Ritz theatre was a fiasco.

Solution (By Examveda Team)

Fiasco : a complete failure, especially a ludicrous or humiliating one.
Triumph : a great victory or achievement.
Victory : an act of defeating an enemy or opponent in a battle, game, or other competition.
Fruitful : (of a tree, plant, or land) producing much fruit; fertile.
Success : the accomplishment of an aim or purpose.

Antonym of Fiasco is Success